A few weeks ago we told you how new high-tech, low-cost air quality sensors are helping valley residents monitor air pollution right outside their homes. But the devices aren’t just being used by homeowners, they’re also being adopted by some of the world’s top scientists. NASA’s Jet Propulsion Laboratory is testing the devices here in the valley, in preparation for investigating pollutants from space.

On a rooftop in Central Fresno stands a forest of air quality monitors. Pipes stick out from the roof, and they’re attached to around a dozen silver and white instruments that look almost like street lights. They’re measuring everything from the size of particulate matter to ozone. This site, run by the California Air Resources Board, is home to most of the instruments that inform Fresno residents of their air quality. And now, this roof is also home to a PurpleAir monitor.

One of the California Air Resources Board's particle counters stands on a roof, with JPL's PurpleAir sensor attached. JPL will compare readings between both instruments.

Credit Laura Tsutsui / Valley Public Radio

The white plastic sensor is smaller than a coffee mug. It hardly stands out next to the other instruments, but it’s doing almost the same job as the machine next to it: measuring particulate matter.

David Diner is a senior research scientist at JPL. His team placed this sensor, and a few others around the Central Valley.

“What we're interested in is looking at atmospheric aerosols,” says Diner. “These are tiny particles that are suspended in the air, and these particles affect our climate and they also affect our health when we breathe them.”

The PurpleAir sensors are consumer-level monitors that measure particulate matter. While the Air Board’s sensors cost thousands of dollars, the PurpleAir costs a little over $200. They’re pretty accurate, but some do warn the data may skew high.

Right now, that PurpleAir sensor JPL has in Fresno is mounted right next to another particle counter so they can compare the readings. Depending on how it performs, JPL may set up more PurpleAir monitors to help with a new research project.

“We're also developing a new instrument called the Multi-Angle Imager for Aerosols or MAIA,” Diner says. “That would launch early in the next decade.”

Part of JPL’s mission is to use robots and satellites to explore space, but they also use them to explore earth. This particular mission is to determine the makeup of particulate matter using the MAIA instrument in space and monitors on the ground. Later, they’ll use health records to look at how the particulate matter affects health.

Bart Ostro is a research professor at U.C. Davis. He’s one of the epidemiologists working with JPL right now to determine which communities the MAIA instrument will focus on.

“It’s going to be looking at a lot of air pollutants that, for parts of the world, have never been measured,” says Ostro. “Many of the countries that they'll be orbiting over simply don't have the resources and the infrastructure to develop monitors of high quality and consistency.”

Ostro says this study is the first of its kind because it’s bringing together ground level data, information from space, and health outcomes.

“I have found that even though there's many studies in the U.S., a lot of countries will not really take notice and take this seriously until and unless you published studies using local data,” Ostro says. “Once you show that, yeah, our own people are susceptible, that often gets the public and policymakers engaged.”

Kevin Hamilton is CEO of the Central California Asthma Collaborative. He agrees that JPL’s study may help them advocate for stronger regulations against local air pollution.

Screen captures of the PurpleAir map shows data from three of JPL's sensors throughout the Central Valley. The orange and red colors indicate the air quality at the time.

Credit PurpleAir.com screenshot

“We really have very good information right now, so I don't expect anything stunning but I am hoping we have more complete data,” says Hamilton.

Hamilton says studies have already been done to show the negative health effects of bad air in the Valley. But the greatest benefit from JPL’s study may be revealing a connection between the types of particulate matter that create certain health outcomes.

“The exposure assessments are the most difficult, because no one writes on a death certificate ‘air pollution caused this death,’” Hamilton says.

While JPL is preparing for this study, there is some doubt over the future of NASA’s earth science mission. President Trump’s nominee for NASA administrator, Congressman Jim Bridenstine, has expressed skepticism that humans are the main cause of climate change. In the past, he introduced legislation that could reduce NASA’s earth science research. However, he has since told a senate committee that he will support the agency’s earth science mission.

The MAIA instrument is predicted to go into space in 2021, and JPL hopes to publish the results in the next decade.

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